A sodium ion conducting gel polymer electrolyte membrane comprising polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) immobilizing a liquid electrolyte of sodium hexa fluorophosphate (NaPF₆) in a junk of ethylene carbonate (EC) and propylene carbonate (PC) is composed by solution cast technique. The membrane has been characterized by impedance spectroscopy and linear sweap voltammetry. The electrolyte membrane possesses ionic conductivity of ∼3.5 mS cm^?1 and an electrochemical stability window of ∼4V.